When a Purchase Order is published, the Contact assigned to the Vendor will be sent an email similar to the one shown below:

When they click the [Sign In] button, they will be taken to these login page:

The first time they login they will be prompted to change their temporary password:

Once done, and moving forward each time they login, they will see the Dashboard for the Vendor Portal:

The buttons on the Dashboard are filters or they can click the Purchase Orders tab to view all Purchase Orders:

Once viewing Purchase Orders they can filter further if needed:

Click on a Purchase Order to view it:

Here they can view, print, or email the Purchase Order:

There is a History and Comments tab where they can view the history as well as add comments with the option of emailing you the comment:

Example comment email below:

They can add a Vendor Reference Number for this Purchase Order by clicking the pencil icon:

When they Accept or Reject the Purchase Order, they will have the option of adding comments, emailing those comments, and adding a Vendor Reference Number (if they have not already done so):

Example acceptance email below:

When accepted or rejected, the Purchase Order in SI 2016 will update with the Vendor Status and Vendor Reference Number.

Note: If you are already have the Purchase Order Explorer open when the Purchase Order is accepted/rejected, you will need to click the [Update From] button in the Vendor Portal section of the ribbon:

They can also manage their profile, change password, and sign out by clicking their name in the upper right corner of the Vendor Portal interface:

SI 2016 Users

The above steps where from the perspective of what your Vendor will see when they log in to the Vendor Portal. You can also view the Purchase Order and of course the History & Comments but clicking the [View] button in the Vendor Portal section of the ribbon: